Merge branch '4.3'

* 4.3:
  [Routing] Fixed unexpected 404 NoConfigurationException
  [DI] Removes number of elements information in debug mode
  [Contracts] Simplify implementation declarations
  Update PR template for 4.3
  [Intl] Add FallbackTrait for data generation
  [Console] Commands with an alias should not be recognized as ambiguous
  clarify the possible class/interface of the cache

composer.json

@@ -37,7 +37,7 @@
         "symfony/yaml": "<3.4"
     },
     "provide": {
-        "symfony/translation-contracts-implementation": "1.0"
+        "symfony/translation-implementation": "1.0"
     },
     "suggest": {
         "symfony/config": "",